The present invention relates to an apparatus for manufacturing a semiconductor device and a method of for manufacturing a semiconductor device by use of the apparatus.
The conventional apparatus for manufacturing the semiconductor device is used to carry out a heat treatment to a semiconductor wafer or to form a thin film over the semiconductor wafer. FIG. 1 is a schematic cross sectional elevation view illustrative of the conventional apparatus for manufacturing the semiconductor device. The conventional apparatus for manufacturing the semiconductor device has the following elements. A chamber 1 is provided for treating semiconductor wafers. The chamber 1 may comprise a quartz-based cylindrically shaped chamber. A heater 2 is provided around a side wall of the cylindrically shaped chamber 1. A quartz boat 6 is accommodated in the cylindrically shaped chamber 1 for mounting plural semiconductor wafers 3. A gas supply type 9 is provided and a gas discharge tube is also provided. A shutter 11 is also provided on a bottom portion of the cylindrically shaped chamber 1. A boat elevator 8 is provided which has a top portion which supports the bottom of the quartz boat 6. A stainless steal scavenger stores the quartz boat 6. The boat elevator 8 is used to move the quartz boat 6 mounting the semiconductor wafers 3 at a speed in the range of 10-20 cm/min. between the stainless steal scavenger and the cylindrically shaped chamber 1, where the cylindrically shaped chamber 1 is heated at a temperature in the range of 700-1200.degree. C. The quartz boat 6 has multiple stages on which the plural semiconductor wafers 3 are mounted. A top level stage of the quartz boat 6 firstly enters into the cylindrically shaped chamber 1 and also finally come out the cylindrically shaped chamber 1. A bottom level stage of the quartz boat 6 finally enters into the cylindrically shaped chamber 1 and also firstly come out the cylindrically shaped chamber 1. This means that the semiconductor wafer mounted on the top level stage of the quartz boat 6 is subjected to the heat treatment in the cylindrically shaped chamber 1 for a longest time, whilst the semiconductor wafer mounted on the bottom level stage of the quartz boat 6 is subjected to the heat treatment in the cylindrically shaped chamber 1 for a shortest time. A difference is caused in the time duration for subjecting the wafer to the heat treatment between the semiconductor wafers 3 over position, whereby a variation in characteristic or performance is caused between the semiconductor wafers 3.
Japanese laid-open patent publication No. 4-297025 discloses a second conventional apparatus for manufacturing the semiconductor device. FIG. 2 is a schematic cross sectional view illustrative of the second conventional apparatus for manufacturing the semiconductor device. A cylindrically shaped main chamber 21 is provided for carrying out a heat treatment to a semiconductor wafer. A heater 22 is also provided around a side wall of the cylindrically shaped main chamber 21. An upper shutter 23 is provided on the top portion of the cylindrically shaped main chamber 21. A lower shutter 24 is provided on the bottom portion of the cylindrically shaped main chamber 21. A wafer boat 26 is provided which has multiple stages for mounting plural semiconductor wafers 3. The wafer boat 26 is supported by a boat elevator 8. A cylindrically shaped top preliminary chamber 20A is further provided over the cylindrically shaped main chamber 21, wherein the cylindrically shaped top preliminary chamber 20A and the cylindrically shaped main chamber 21 are separated from each other by the above upper shutter 23. The bottom portion of the cylindrically shaped top preliminary chamber 20A is separated by the above upper shutter 23 from the top potion of the cylindrically shaped main chamber 21. A top shutter 27 is also provided on the top portion of the cylindrically shaped top preliminary chamber 20A. A cylindrically shaped bottom preliminary chamber 20B is further provided under the cylindrically shaped main chamber 21, wherein the cylindrically shaped bottom preliminary chamber 20B and the cylindrically shaped main chamber 21 are separated from each other by the above lower shutter 24. The top portion of the cylindrically shaped bottom preliminary chamber 20B is separated by the above lower shutter 24 from the bottom potion of the cylindrically shaped main chamber 21. A bottom shutter 25 is also provided on the bottom portion of the cylindrically shaped bottom preliminary chamber 20B. In a first step, the bottom shutter 25 is opened to enter the wafer boat 26 into the cylindrically shaped bottom preliminary chamber 20B and then the bottom shutter 25 is closed. In a second step, the lower shutter 24 is opened to move the wafer boat 26 from the cylindrically shaped bottom preliminary chamber 20B to the cylindrically shaped main chamber 21 and then the lower shutter 24 is closed for subsequent heat treatment to the semiconductor wafers 3 amounted on the wafer boat 26. After the heat treatment was carried out, the upper shutter 23 is opened to move the wafer boat 26 from the cylindrically shaped main chamber 21 into the cylindrically shaped top preliminary chamber 20A. This second conventional apparatus for manufacturing the semiconductor device is free from the above problem engaged with the first conventional apparatus. Namely, a top level stage of the wafer boat 26 firstly enters into the cylindrically shaped main chamber 21 and also firstly come out the cylindrically shaped main chamber 21. A bottom level stage of the wafer boat 26 finally enters into the cylindrically shaped chamber 1 and also finally come out the cylindrically shaped main chamber 1. This means that no difference is caused in the time duration for subjecting the wafer to the heat treatment between the semiconductor wafers 3 over position, whereby no variation in characteristic or performance is caused between the semiconductor wafers 3. The above second conventional apparatus has the two preliminary chambers, for which reason the above second conventional apparatus is much higher in height than the first conventional apparatus. Namely, a high roof of a storage room for installing the apparatus is necessary. Otherwise, it is necessary to reduce the height of each of the cylindrically shaped main chamber 21 and the top and bottom preliminary chambers 20A and 20B. This reduction in the height of each of the cylindrically shaped main chamber 21 and the top and bottom preliminary chambers 20A and 20B requires a reduction in height of the wafer boat 26 or reduction in the number of the multiple stages for mounting the wafers. Namely, the number of the semiconductor wafers 3 mounted on the single wafer boat 26 is reduced. A productivity of the semiconductor device is thus reduced.
Japanese laid-open patent publication No. 6-349752 discloses a third conventional apparatus for manufacturing a semiconductor device FIG. 3 is a schematic perspective view illustrative of the third conventional apparatus for manufacturing the semiconductor device. A reactor 35 is provided which has a cylindrically shaped reactor core 31 which extends in a vertical direction. The reactor 35 comprises a rear portion and a front portion, wherein a rear half of the cylindrically shaped reactor core 31 is formed in the rear portion of the reactor 35 and a front half of the cylindrically shaped reactor core 31 is formed in the front portion of the reactor 35. The rear portion of the reactor 35 has a heater 35. The front portion of the reactor 35 comprises a pair of doors 33 and 34 to make an opening 36 between them. Namely, the doors 33 and 34 may slide in the direction parallel to the arrow marks "A" and "B" and on the rear portion of the reactor 35. The opening 36 between the opened doors 33 and 34 extends along a longitudinal center axis of the cylindrically shaped reactor core 31. Namely, a rear half portion 31a of the cylindrically shaped reactor core 31 is formed in the rear portion of the reactor 35. A front right quarter portion 31b of the cylindrically shaped reactor core 31 is formed in the right door 33. A front left quarter portion 31c of the cylindrically shaped reactor core 31 is formed in the left door 34. A wafer boat 38 is provided which extends along the longitudinal center axis of the cylindrically shaped reactor core 31. The wafer boat 38 has multiple stages for mounting the semiconductor wafers 3 which are aligned along the longitudinal center axis of the cylindrically shaped reactor core 31. The bottom of the wafer boat 38 is connected with a driver mechanism 39 for moving the wafer boat 38. The above pared doors 33 and 34 comprising the front part of the reactor 31 are opened to make the opening 36 so that the driver mechanism 39 is operated to move the wafer boat 38 mounting the semiconductor wafers 3 to the rear half portion 31a of the cylindrically shaped reactor core 31 formed in the rear portion of the reactor 35. The paired doors 33 and 34 are then closed so that the wafer boat 38 mounting the semiconductor wafers 3 are accommodated in the cylindrically shaped reactor core 31. This third conventional apparatus for manufacturing the semiconductor device is also free from the above problem engaged with the first conventional apparatus. Namely, all of the stages of the wafer boat 38 concurrently enter into the cylindrically shaped main chamber 21 and also firstly come out the cylindrically shaped reactor core 31. This means that no difference is caused in the time duration for subjecting the wafer to the heat treatment between the semiconductor wafers 3 over position, whereby no variation in characteristic or performance is caused between the semiconductor wafers 3. However, a far portion of each wafer from the wafer boat 38 firstly enters into the cylindrically shaped reactor core 31, whilst a close portion of each wafer to the wafer boat 38 finally enters into the cylindrically shaped reactor core 31. A difference is caused in the time duration of receiving the heat treatment between the far portion of each wafer from the wafer boat 38 and the close portion of each wafer to the wafer boat 38. Namely, a in-plane variation in the time of receiving the heat treatment is caused between the lateral position for each wafer, even no variation in the time of receiving the heat treatment is caused between the wafers. Further, the heater 35 is not ring-shaped. The heater 35 is unwillingly discontinued at the opening portion 36 between the paired doors 33 and 34, whereby the heater 35 is incapable of a uniform heating property around the cylindrically shaped reactor core 31. This causes a variation in the amount of receiving the heat over position for each wafer.
In the above circumstances, it had been required to develop a novel apparatus for manufacturing a semiconductor device free from the above problem.